feat: add langchain service

Azure-Samples · Sep 1, 2023 · f23b342 · f23b342
1 parent e43d22e
commit f23b342
Show file tree

Hide file tree

Showing 5 changed files with 70 additions and 8 deletions.
diff --git a/packages/api/src/lib/approaches/approach-base.ts b/packages/api/src/lib/approaches/approach-base.ts
@@ -1,5 +1,5 @@
 import { SearchClient } from '@azure/search-documents';
-import { OpenAiClients } from '../../plugins/openai.js';
+import { OpenAiService } from '../../plugins/openai.js';
 import { removeNewlines } from '../util/index.js';
 
 export interface SearchDocumentsResult {
@@ -11,7 +11,7 @@ export interface SearchDocumentsResult {
 export class ApproachBase {
   constructor(
     protected search: SearchClient<any>,
-    protected openai: OpenAiClients,
+    protected openai: OpenAiService,
     protected chatGptModel: string,
     protected sourcePageField: string,
     protected contentField: string,

diff --git a/packages/api/src/lib/approaches/ask-retrieve-then-read.ts b/packages/api/src/lib/approaches/ask-retrieve-then-read.ts
@@ -1,5 +1,5 @@
 import { SearchClient } from '@azure/search-documents';
-import { OpenAiClients } from '../../plugins/openai.js';
+import { OpenAiService } from '../../plugins/openai.js';
 import { messagesToString } from '../message.js';
 import { MessageBuilder } from '../message-builder.js';
 import { AskApproach } from './approach.js';
@@ -33,7 +33,7 @@ const ANSWER = `In-network deductibles are $500 for employee and $1000 for famil
 export class AskRetrieveThenRead extends ApproachBase implements AskApproach {
   constructor(
     search: SearchClient<any>,
-    openai: OpenAiClients,
+    openai: OpenAiService,
     chatGptModel: string,
     sourcePageField: string,
     contentField: string,

diff --git a/packages/api/src/lib/approaches/chat-read-retrieve-read.ts b/packages/api/src/lib/approaches/chat-read-retrieve-read.ts
@@ -1,5 +1,5 @@
 import { SearchClient } from '@azure/search-documents';
-import { OpenAiClients } from '../../plugins/openai.js';
+import { OpenAiService } from '../../plugins/openai.js';
 import { ChatApproach, ApproachResponse } from './approach.js';
 import { ApproachBase } from './approach-base.js';
 import { HistoryMessage, Message, messagesToString } from '../message.js';
@@ -45,7 +45,7 @@ export class ChatReadRetrieveRead extends ApproachBase implements ChatApproach {
 
   constructor(
     search: SearchClient<any>,
-    openai: OpenAiClients,
+    openai: OpenAiService,
     chatGptModel: string,
     sourcePageField: string,
     contentField: string,

diff --git a/packages/api/src/plugins/langchain.ts b/packages/api/src/plugins/langchain.ts
@@ -0,0 +1,49 @@
+import fp from 'fastify-plugin';
+import { OpenAIChatInput } from 'langchain/dist/types/openai-types';
+import { ChatOpenAI } from 'langchain/chat_models/openai';
+import { OpenAIEmbeddings } from 'langchain/embeddings/openai';
+
+export type LangchainService = {
+  getChat(): Promise<ChatOpenAI>;
+  getEmbeddings(): Promise<OpenAIEmbeddings>;
+};
+
+export default fp(
+  async (fastify, opts) => {
+    const config = fastify.config;
+    const getAzureOpenAiOptions = (apiToken: string) => ({
+      azureOpenAIApiVersion: fastify.openai.config.apiVersion,
+      azureOpenAIApiKey: apiToken,
+      azureOpenAIBasePath: `${fastify.openai.config.apiUrl}/openai/deployments`,
+      azureOpenAIApiDeploymentName: config.azureOpenAiChatGptDeployment,
+    });
+
+    fastify.decorate('langchain', {
+      async getChat(options?: Partial<OpenAIChatInput>) {
+        const apiToken = await fastify.openai.getApiToken();
+        return new ChatOpenAI({
+          ...options,
+          ...getAzureOpenAiOptions(apiToken),
+        });
+      },
+      async getEmbeddings(options?: Partial<OpenAIChatInput>) {
+        const apiToken = await fastify.openai.getApiToken();
+        return new OpenAIEmbeddings({
+          ...options,
+          ...getAzureOpenAiOptions(apiToken),
+        });
+      },
+    });
+  },
+  {
+    name: 'langchain',
+    dependencies: ['azure', 'config', 'openai'],
+  },
+);
+
+// When using .decorate you have to specify added properties for Typescript
+declare module 'fastify' {
+  export interface FastifyInstance {
+    langchain: LangchainService;
+  }
+}
diff --git a/packages/api/src/plugins/openai.ts b/packages/api/src/plugins/openai.ts
@@ -3,9 +3,14 @@ import { AccessToken } from '@azure/core-http';
 import { OpenAI } from 'openai';
 import { Chat, Embeddings } from 'openai/resources/index';
 
-export type OpenAiClients = {
+export type OpenAiService = {
   getChat(): Promise<Chat>;
   getEmbeddings(): Promise<Embeddings>;
+  getApiToken(): Promise<string>;
+  config: {
+    apiVersion: string;
+    apiUrl: string;
+  };
 };
 
 const AZURE_OPENAI_API_VERSION = '2023-05-15';
@@ -53,6 +58,14 @@ export default fp(
         await refreshOpenAiToken();
         return embeddingsClient.embeddings;
       },
+      async getApiToken() {
+        await refreshOpenAiToken();
+        return openAiToken.token;
+      },
+      config: {
+        apiVersion: AZURE_OPENAI_API_VERSION,
+        apiUrl: openAiUrl,
+      },
     });
   },
   {
@@ -64,6 +77,6 @@ export default fp(
 // When using .decorate you have to specify added properties for Typescript
 declare module 'fastify' {
   export interface FastifyInstance {
-    openai: OpenAiClients;
+    openai: OpenAiService;
   }
 }